# curs_clear 3x

    curs_clear(3x)                                           curs_clear(3x)

## NAME

           erase, werase, clear, wclear, clrtobot, wclrtobot,
           clrtoeol, wclrtoeol - clear all or part of a curses window

## SYNOPSIS

           # include <curses.h>

           int erase(void);
           int werase(WINDOW *win);
           int clear(void);
           int wclear(WINDOW *win);
           int clrtobot(void);
           int wclrtobot(WINDOW *win);
           int clrtoeol(void);
           int wclrtoeol(WINDOW *win);

## DESCRIPTION

           The  erase  and werase routines copy blanks to every posi-
           tion in the window, clearing the screen.

           The clear and wclear routines are like erase  and  werase,
           but  they also call clearok, so that the screen is cleared
           completely on the next call to wrefresh  for  that  window
           and repainted from scratch.

           The  clrtobot and wclrtobot routines erase from the cursor
           to the end of screen.  That is, they erase all lines below
           the  cursor  in the window.  Also, the current line to the
           right of the cursor, inclusive, is erased.

           The clrtoeol and wclrtoeol routines erase the current line
           to  the  right of the cursor, inclusive, to the end of the
           current line.

           Blanks created by erasure have the current background ren-
           dition (as set by wbkgdset) merged into them.

## RETURN VALUE

           All  routines  return the integer OK on success and ERR on
           failure.  The SVr4.0 manual says "or a non-negative  inte-
           ger if immedok is set", but this appears to be an error.

           X/Open  defines  no error conditions.  In this implementa-
           tion, functions using a window pointer parameter return an
           error if it is null.

## NOTES

           Note that erase, werase, clear, wclear, clrtobot, and clr-
           toeol may be macros.

## PORTABILITY

           These functions are described in the XSI Curses  standard,
           Issue  4.   The standard specifies that they return ERR on
           failure, but specifies no error conditions.

           Some historic curses implementations had,  as  an  undocu-
           mented  feature,  the  ability  to  do  the  equivalent of
           clearok(..., 1) by saying touchwin(stdscr)  or  clear(std-
           scr).  This will not work under ncurses.

           This  implementation, and others such as Solaris, sets the
           current position to 0,0 after  erasing  via  werase()  and
           wclear().   That fact is not documented in other implemen-
           tations, and may not be true of implementations which were
           not derived from SVr4 source.

           Not  obvious  from  the  description, most implementations
           clear the screen after wclear even for a subwindow or  de-
           rived window.  If you do not want to clear the screen dur-
           ing the next wrefresh, use werase instead.

## SEE ALSO

           curses(3x), curs_outopts(3x), curs_refresh(3x)

                                                             curs_clear(3x)